The flu is contagious for about 24 hours after your fever breaks. Find out more about avoiding the spread of the flu and when you’re contagious.

Published: January 9, 2023 | Updated: April 12, 2024

The flu is contagious for about 24 hours after your fever breaks. The Centers for Disease Control and Prevention advises staying home for at least 24 hours after your fever goes away without the help of ibuprofen (Motril or Advil) or acetaminophen (Tylenol).

“Overall, you can be contagious or were contagious the day before you noticed any symptoms. You still can spread the flu for about a week after you started feeling sick or as long as you have symptoms,” said Rachel Alexander, APRN, nurse practitioner with Norton eCare.

Cover coughs and sneezes and wash hands even after you return to work or school. Keep in mind that even if your symptoms don’t include a fever, you still may have the flu and may be contagious.

Typically, you’re most contagious during the first three to four days after you start feeling ill. Infants and people with weakened immune systems may be contagious with the flu for more than a week.

Flu symptoms

Those who have the flu can have all or some of the following symptoms. Even if you don’t have a fever, you still may have influenza.

• Fever
• Cough
• Sore throat
• Runny or stuffy nose
• Body aches
• Headache
• Chills
• Fatigue
• Diarrhea and vomiting

Emergency flu symptoms

The flu should be taken seriously. The following symptoms are an emergency needing medical care right away.

In children:

• Fast breathing or trouble breathing
• Bluish skin color
• Not drinking enough fluids
• Not waking up or not interacting
• Being so irritable that the child does not want to be held
• Flu-like symptoms that improve but then return with fever and worse cough
• Fever with a rash

In adults:

• Difficulty breathing or shortness of breath
• Pain or pressure in the chest or abdomen
• Sudden dizziness
• Confusion
• Severe or persistent vomiting